<!-- 钩子函数 页面挂载 --> 
<script src="vue.js"></script> 
  <div id="app"> 
 
<p>{{msg}}</p >
  </div> 
 
  <script> 
    var vue = new Vue({  
        el:'#app', 
        data: {  
            msg:"我又回来了",
  },
    mounted(){  
        console.log("页面挂载之后"); 
        console.log(this.$el.innerHTML) 
  }, 
    beforeMount(){  
        console.log("页面挂载之前"); 
        console.log( this.$el.innerHTML) 
    }
  }) 
  </script>